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Exhaust flare/flashes

gecko

gecko

Charter Member
I'm looking to rework my exhaust flare effects, but it's really difficult to find info on what they should look like. Youtube has been somewhat helpful, but I'm still not understanding them. They seem to be visible at some times and not at others. What causes it? Is it only visible in low light? Low or high throttle setting? A certain mixture setting? Do certain engine types have more or less of this effect? Hopefully someone here is more knowledgeable in this area than I. Thanks for any help,

Daniel
 
I've always thought that the constant flame effect in some cfs3 aircraft is overmodelled.

However I know that the Hurricanes used as night fighters had small cowls fitted above and behind the exhausts to prevent affecting the pilots vision so there must be something their in certain conditions.

I also checked out You tube but that doesn't shed any more light on it either, more smoke than anything else.

There is a good scene in the BoB movie with Spits are starting with some impressive licks of flame belching out if the exhausts.

>Not much help really, was it Daniel. :icon_lol:
 
That's why it mystifies me - lot's of equipment added to night fighters to reduce its visibility and save the pilot's night vision, but photos and videos don't capture it. I agree, it does seem overdone in our aircraft sometimes, but it seems there should be something there - trying to find a happy and realistic medium...

Start up is another matter, lots of videos showing flames out from the exhaust stacks as the cylinders fire, but it's gone soon after. Our current effects aren't too bad in this respect.
 
The real thing

Saw this more than a year ago. Remember this Reno racing Fury uses a customised Wright R3350 engine and so is a tad more powerful than any WW2 engine, but you'll get the idea.

September Fury
 
exhaust

Several ww2 films do show flames for fighters only at night or dusk/dawn. I have read that the exhaust shrouds on Lancasters and the manifolds on the Halifaxes glowed a dull red and there were seen by Luftwaffe crews and used to guide the fighters to attack. No one has ever created reasonable red glowing effects (someone did make red flames though). The blue is nice but that is for the high quaity allied fuel. German exhaust tended to be more orange/blue. I think the fact that the flames are intermittent is a good thing as it tends to model the pulsing of exhaust and misfires and such.

Hope this muddies up things for you......:icon_lol:
 
Hairyspin, that video is quite impressive! I recall reading someone's account of flying a Spitfire and noted the flames came close to all the way back to the canopy, this gives a pretty good idea of what it would look like...it would seem this only happens at high throttle settings? Also, doesn't seem to be very visible in daylight.

Ted, great tip on the color based on fuel quality - where do you find info like that? Would this be a difference between 87 and 100 octane fuels, or actual production quality of comparable grade fuels? Interesting about the glowing exhaust shrouds - would that be the entire shroud, or just part? I may try to cook something up. Did any other planes have this problem?

Thanks guys - slowly getting the picture of what I need to do...
 
The Fairey Barracuda had an exhaust manifold which took any flames down the fuselage side and completely out of the pilot's line of sight. Unfortunately the flames made the thing glow bright enough to be seen a mile or more away and it was dropped in later marks for standard exhaust stacks.

186183d1323604991t-british-light-bombers-reconnaissance-aircrafts-fairey-barracuda-003.jpg
fairey_barracuda_ii_1881309.jpg
 
So if I read you right, the first pic would have a red glow of hot metal all down the exhaust manifold (no visible flames), while the second assumedly might have a similar effect (at a high power setting) as the Sea Fury in the video you posted?
 
Yes, pretty much like that. Comparing the Barracuda's plain pipe with a Wellington's flame damper exhaust you can see the effort made to reduce both flame visibility and glowing metal. The two pipes extend inside to the far end and the exhaust gases then have to travel back up towards the front before exiting one of the many exhaust fins. There's a large external area in the propellor wash to cool the hot gases and a long route through the unit for flames to travel if they're to show outside.

With today's infra-red sights they'd be dead meat anyway .... :tgun2:
 
Reckon so: what about the back pressure??

Bristol Hercules ( a la beau. engines) on MK30/31 Freighters had stub 'ejector exhausts'. very short pipes 2 cylinders siamesed into each stack. 9 of around the ring cowl: airflow over the tip of stacks extracted gas for performance.

Deafeing (literally) noise at take-off; bright blue mixed with streaks of yellow through it; fierce and scary looking like an oxy-torch flame. Fiddling with a torch would give you the idea (changing acetylene ratio). Smaller but similar colurs in cruise at night; some intermittancy with blue and yellow mixing, but mostly blue. [Was on 130 Grade/Green high octane Avgas.]

C54/DC4 had similar colours from single exit from collector ring pipe (4 per a/c) at take-off. PW R2000. Probably a little at cruise, (harder to see underneath.)

Don't know if this is O/T or not: (the colours would be similar.)
 
Nope, right on topic!

Were these effects visible in daylight, or just at night?

The problem is that CFS3 doesn't have a way to control effects based on what the engine is doing at the time. My current effects are based on hairyspin's video, blue with an orange base and very flikery (different timings for each manifold) and an orange version for aircraft using 87 octane or B-4 AvGas. They come on at approximately 65% of the aircraft's top speed at sea level and are quite visible at night but hard to pick out during the day.

If there were a way to base effects on throttle setting, it would be way better. AFAIK this is only possible with jets in CFS3. If that were possible then the effects would show any time you're at full throttle (including take off).

Here's a couple WIP shots...am I close?

100/130 Octane (German C-2 and C-3 fuels)
View attachment 66150

87 Octane (German B-4)
View attachment 66149


You kind of have to use your imagination with these shots as it's impossible to capture the flickering of the different manifolds properly in a picture.

Daniel
 
The first screenshot looks more convincing to me. Matching the September Fury video would be a bit OTT considering how over-boosted these race engines are: a service a/c had to be usable over a good number of missions, rather than needing a full overhaul after just a couple.
 
From what I've been reading here (especially icutler's post), it would seem that although September Fury's engines is way over-boosted, the effect it shows at full throttle is typical for these larger engines, even wartime ones? Please correct me if I'm wrong. BTW, the second shot is the exact same effect as the first, but with the colors changed to reflect lower grade fuel as per Ted's post.
 
September Fury uses an engine that in wartime form generated from 2200hp to over 3500hp depending on the model - and then SF has fuel injection and cunning intake air ducting to raise the available boost sky-high: who knows how much more power that gives? 4000+ hp?

An original Sea Fury's Centaurus generated 2300hp typically with similarly short exhaust pipes, so I think SF will show much longer flames at night. Interesting subject and a worthwhile mod, please keep at it!

btw, the well-known photos of Spitfires and others belching huge flames at startup are the result of over-priming before pushing the starter and boost coil buttons :icon_eek:
 
Shorter seems reasonably plausible...does anyone know of wartime accounts where this might be described?

Re engine starts, this seems to have happened often, given the amount it shows up in period videos (what few there are). Seems to happen a lot less current videos of restored aircraft, I guess the owners are being a bit more careful...
 
The effects in those shots look to be a big impovement Daniel.


and very flikery (different timings for each manifold)
Click to expand...

Have you managed to get flames from the individual exhaust stubs then? :)
 
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